There are multiple ways reliability is expected, of which the common performance parameters of the method, the similar product of analogy method, the failure rate is expected to method and expert grading method, each method is expected to have a specific area of research and its own defects, and the research and development of conventional ammunition is expected and the reliability of the distribution and no specific research methods, in order to study the reliability prediction and allocation, in the process of research and development of conventional ammunition based on similar products of analogy method, through the design of a new developed product with similar structure of “ideal” model, adopt the structure of “ideal” failure rate to judge the research method of the new developed product failure rate on the reliability of the new developed products and distribution is expected. By establishing the mathematical model of the reliability of the structure of “ideal”, use “similar products of analogy method” to carry out targeted comparison, to find out the correct factors, so as to determine the reliability of the new developed product. Through example calculation, the launch of new research products, exterior ballistic flight safety and reliability of the finish effect is expected and distribution, the results show that the method is convenient and easy to use and can relatively accurately estimated failure rate of the new developed products, for reliability prediction and allocation in the process of research and development of conventional ammunition provides a new way of thinking, The method has the certain practical guiding significance.