The reflector of the astromesh deployable antenna is formed with metallic net fixed on the nodes of its astromesh. The astromesh determines shape of the reflector, so analysis of the astromesh is necessary. With force density method and paraboloid equation, balance equations of the astromesh were set up at first. Length and tension of the cords, coordinates of the nodes and outer forces on the nodes were included in the equations. After the coefficient matrix was transformed, a group of orthogonal normalization basis in its null space was obtained. Solving method of the balance equations was analyzed. After optimized with the genetic algorithm, initial tensions of all cords were obtained finally. The analysis method can make design of the astromesh more rational and reliable.