It is one of the basic principles of criminal procedure to appeal without additional punishment. For an appellant who has a defendant in the same criminal case, the court of second instance shall not increase the punishment of the defendant who appealed, nor shall it increase the punishment of other defendants who have not appealed.
Criminal procedure law
Article 226 The people's court of second instance shall not increase the punishment of the defendant when trying the case appealed by the defendant, his legal representative, defender or close relatives. The people's court of second instance shall not increase the punishment of the defendant unless there are new criminal facts, and the people's procuratorate shall make supplementary prosecution.
Where a people's procuratorate lodges a protest or a private prosecutor lodges an appeal, it shall not be restricted by the provisions of the preceding paragraph.
Article 310 When trying a case of appeal or protest, the people's court of second instance shall conduct a comprehensive review of the facts ascertained in the judgment or ruling of first instance and the applicable law, and shall not be limited by the scope of appeal or protest.
Article 311 In the same criminal case, if only some defendants appealed, or the private prosecutor appealed against only some defendants' judgments, or the people's procuratorate protested against only some defendants' judgments, the people's court of second instance shall examine the whole case and deal with it together.
The Supreme People's Court's Interpretation on the Application of the Criminal Procedure Law of People's Republic of China (PRC)
Article 325 When trying a case appealed by the defendant, his legal representative, defender or near relative, the defendant's punishment shall not be aggravated, and the following provisions shall be implemented:
(1) If only some defendants appeal in a case tried in the same case, the appellant's punishment shall not be aggravated, nor shall the punishment of other defendants in the same case be aggravated;
(2) If the facts in the original judgment are clear and the evidence is true and sufficient, but the charges identified are improper, the charges may be changed, but the punishment may not be aggravated;
(3) If the defendant is punished for several crimes in the original judgment, the penalty decided to be executed shall not be aggravated, nor shall the penalty for one of several crimes be aggravated;
(4) If the defendant is suspended in the original judgment, the probation period of probation shall not be revoked or extended;
(5) If the injunction was not announced in the original judgment, the announcement shall not be increased; If the original judgment declares an injunction, the content shall not be increased or the time limit extended;
(six) the original judgment sentenced the defendant to death with a suspension of execution, and there is no restriction on commutation;
(7) If the facts in the original judgment are clear and the evidence is true and sufficient, but the punishment imposed is too light, and additional punishment should be applied but not applied, the punishment shall not be directly aggravated or applied, nor shall it be sent back to the people's court of first instance for retrial on the grounds of unclear facts and insufficient evidence. If the sentence must be changed according to law, it shall be retried in accordance with the procedure of trial supervision after the judgment or ruling of second instance takes effect.
Cases protested by people's procuratorates or appealed by private prosecutors shall not be restricted by the provisions of the preceding paragraph.