procedure of lossing China passport in Laos, Vientiane? thanks and how many days to get a new one ?K

You can try to reapply for a Chinese passport from the Chinese embassy or consulate general.
First, make an online appointment for the application. Prepare your passport and its copy, a completed application form, and 3 passport-style photos, the loss record of your passport, as well as other documents the consular officers consider necessary, and then submit the application to the embassy or the consulate where you resides.