The discrepancy between input and output in a typical serial manufacturing system is always exists, due to workstation reliability and stochastic factors. The novel system reliability concept that takes customer needs into account has been redefined. On the basis of description of serial manufacturing system with checking machine (SMSCM), system reliability evaluation method has been put forward based on production effectiveness. The proposed method framework applying to a cylinder production line case has been proved to be efficient and effective to the system reliability problem of serial manufacturing system under OTD lot production. The interactive relationship between system reliability and time unit or order lot-sizing is remarked as well, which provide some guidance.