In order to deal with the difficulty of technical risk direct measurement and the strong subjectivity for model parameter setting, the TRL (technology readiness level) as a standard method, was applied for evaluating the condition and the difficulty of technology realization. The quantitative relations were built by system representation with matrix and relation inference between the TRLs of all subsystems and the dynamic parameters of system process model. Then the uncertainties of schedule and cost beyond tolerable range were evaluated by the indirect method of system process modeling and simulation for the technical risk assessment of complex system development. Additionally, to improve the system resolution for analysis, the multi-resolution modeling method is designed to update the assessment continuously and to improve the analytical resolution along with system evolution.