2. Protect the filing date to avoid the loss of novelty: All PCT member countries recognize the international filing date and priority date of PCT as the national filing date and priority date when they enter the national phase.
3. Avoid the waste of patent fees: before determining the market value, take the lowest fee as the basic filing date to ensure a relatively long time (30 months).
4. Save the cost and process in the national stage: use the international retrieval and preliminary examination opinions of PCT international stage to modify the patent specification and patent application scope and improve the approval rate; After entering the national stage, we can avoid unnecessary refutation and modification of defense procedures.