In order to reduce the volume of SoC test data,this paper proposes a technique based on variational reference sub-vector(RSV)and Errorcorrecting code(ECC)to compress the test data.Taking advantage of ECC and the percentage of dont care bits in the test data volumes,the original test data with ECC is encoded to generate larger number of matching patterns.Practical experiments are implemented on ISCAS 89 benchmark circuits with the condition of single scan chain.This paper has compared the compression ratio of the proposed method with those of other relative compression methods,and the results show that our method leads as high as 30%over the other methods.Besides,by reducing the test data,our method can save the memory of the automatic test equipment(ATE)so that it will save the cost for circuit test.