Based on the finite element method,which is based on a navigation power junction project,we adopt the nonlinear theory to establish the two dimensional simulation model of lock chamber structure in maintenance and low water operation respectively for the contact analysis and calculation of highly lined inverted trapezoidal lock chamber structure and rock bed.According to the research on the stress distribution of the contact state and contact part,we draw the conclusion that the weak surface of the inverted trapezoidal lock chamber structure may be on the steps.