Smart grid dispatching and control system (SGDCS) is an integrated system for dispatching production business, which provides technical support for power grid operation monitoring, analysis, control, planning, evaluation, and dispatching management. It consists of four main kinds of applications, real time monitoring and early warning, scheduling planning, security checking and scheduling management. As a long-running infrastructure software, its reliability is critical to the availability of the smart grid operations. How to evaluate the reliability of this systems attracts more and more attentions. In this work, we adopt software reliability testing techniques to smart grid dispatching and control system and propose a series of methods to construct the operation profiles, generate test cases and evaluate the reliability of it. A case study based on SCADA system (an implementation of SGDCS, produced by NARI Inc.) is conducted to prove the feasibility of proposed methods and the efficiency of proposed workflows.