In order to improve the efficiency of equipment reliability work, this paper analyzed the benefit of reliability investment and the relationship between reliability and LCC. From the point of view of economy, a concept of “the Contribution Rate of Reliability Index Adjustment to LCC” was put forward to optimize the reliability index design in the demonstration and development stage by the reverse analysis which is tracked by cost. By defining and solving the concept in two cases, the integrated balance between reliability requirements and LCC target was realized, which has certain reference value in determining the investment scale and improving the benefit of reliability investment and cost-effectiveness ratio. An example was showed to illuminate the method and decision-making process.