Based on the “immune system theory” and “spatial effect theory”, the mechanism of poverty alleviation audit to improve the quality of poverty alleviation is analyzed. Take the data of 61 former national poverty-stricken counties in Sichuan Province from 2011 to 2019 as samples, the multi-period double difference model and spatial Dobbin model are used for empirical test. The results show that poverty alleviation audit is helpful to the the poverty alleviation quality, and it also has obvious spatial spillover effect. In this research, the measurement accuracy of the poverty alleviation quality is improved and the path for poverty alleviation audit to promote poverty alleviation quality is clarified, providing reference to the key points of the whole process poverty alleviation audit and the improvement of regional collaborative audit.