Abstract: Abstract: Understanding the evolution law of the advance support pressure is an important basis for determining the advance support distance. Based on the engineering background of a deep mine thick seam fully mechanized caving face, this paper uses the methods of field monitoring, theoretical analysis and numerical simulation, the evolution law of advance support pressure is studied, and the reasonable advance support distance is determined. The following conclusions are drawn: Advanced abutment pressure is based on the time and space series, which is periodic, and the period is consistent with the roof breaking period; Compared with the analysis of the stress variation of "single measuring point", the advance support distance obtained by analyzing the stress variation characteristics of "whole monitoring area" is more reasonable and accurate; When no mining monitoring area is pushed, its stress curve presents the shape of "near-high, far-low". When mining monitoring area is pushed, its stress curve presents the shape of "near-horizontal", with the distance of near-horizontal span being 90m.