In order to solve the fault tolerance and reliability problems of quantum circuit, a series of structural equivalence rules and optimization operation strategies of quantum circuit are proposed to minimize the number of T gates, increase T gate depth, minimize circuit level, reduce fault tolerance implementation costs and increase circuit reliability. In order to satisfy the nearest neighbor constraints of some quantum systems, a LNN (linear nearest neighbor) arrangement algorithm based on Clifford + T gate quantum circuit is presented. Experiments are done on some benchmarks of RevLib, the results show that the optimization rate of most functions and the running time of the algorithm are better than those of the existing literature.