Due to the limitations of the existing fault detection methods in the embryonic cellular array (ECA),the fault detection coverage cannot reach 100％.In order to evaluate the reliability of the ECA more accurately,embryonic cell and its input and output (I/O) resources are considered as a whole,named functional unit (FU).The FU fault detection coverage parameter is introduced to ECA reliability analysis,and a new ECA reliability evaluation method based on the Markov status graph model is proposed.Simulation experiment results indicate that the proposed ECA reliability evaluation method can evaluate the ECA reliability more effectively and accurately.Based on the proposed reliability evaluation method,the influence of parameters change on the ECA reliability is studied,and simulation experiment results show that ECA reliability can be improved by increasing the FU fault detection coverage and reducing the FU failure rate.In addition,by increasing the scale of the ECA,the reliability increases to the maximum first,and then it will decrease continuously.ECA reliability variation rules can not only provide theoretical guidance for the ECA optimization design,but also point out the direction for further research.