Virtual simulation of maintainability is an important tool for aircraft structure and systems design， in which the rapid generation of appropriate virtual human maintenance posture is crucial to the efficiency and feasibility of maintainability analysis. Aiming at the problems of low efficiency and limited applicability of the current virtual human maintenance posture solving methods， a virtual maintenance posture layered solving method for the narrow space of aircraft was proposed. In the method， with the waist as the demarcation point， the maintenance posture was decomposed into two parts： upper body and lower body， and Elitist Nondominated Sorting Genetic Algorithm Ⅱ （NSGA-Ⅱ） was used to optimize and solve them respectively to obtain the overall maintenance posture. Firstly， the maintenance posture optimization criterion was constructed by considering the space limitations and human body structure constraints comprehensively. Secondly， multi-objective optimization models of upper body and lower body postures were constructed on the basis of the maintenance posture optimization criterion through analyzing geometry and inverse kinematics principles， and NSGA-Ⅱ was applied to solve them sequentially. Through analysis of cases of disassembly of aircraft cockpit Air Data Module （ADM） and cargo promotion in cargo hold， it is verified that the proposed method can generate virtual maintenance posture in narrow space of aircraft effectively， and has good applicability and feasibility.