The contract says: "Party A can adjust Party B's post because of work needs." Will Party A change my department without my consent?

In principle, yes. The work needs are determined by the unit's unilateral will, without the consent of the employee, except that the employee has evidence to prove that it is not the work needs but other reasons, or the job position is obviously not suitable for the employee. In this case, employees can apply for labor arbitration to safeguard their rights.