The software reliability of component-based development depends on component reliability，but component reliability is affected by test coverage and usage frequency.Therefore，the reliability evaluation of new components is often low.When a newly developed component is introduced into mature software，no matter the importance of component，the software reliability evaluation value will change greatly.To solve this problem，taking a software as the research object， a Markov chain software model based on functional scenario is established. the importance of each component in the model is evaluated by analytic hierarchy process.On this basis，a software reliability evaluation model based on component importance is established.The simulation results show that the model can more accurately reflect the software reliability level of component-based development.

The guidance system of air defense missile contains many index elements. The current optimization of the guidance system is often only for a specific index， but the optimization of a single index does not mean the optimal comprehensive performance， or even the situation that a single index is better but the comprehensive performance of the system decreases. Therefore， it is necessary to establish the mathematical relationship between comprehensive performance and each index， and find an optimization algorithm to meet the needs of comprehensive performance optimization and relevant constraints of index elements at the same time. Taking Patriot-3 air defense missile as the research goal， the performance evaluation system of guidance system is established. A combined simplex and augmented Lagrangian method is used to optimize the guidance system with respect to the process constraints and objective functions. The simulation results show that this method can effectively improve the comprehensive performance of the guidance system.