The invention discloses a highly-sensitive primer composition and detection method for detection of epidermal growth factor receptor (EGFR) gene mutation. The primer composition comprises two upstreamprimers, a probe and a downstream primer, wherein the first upstream primer is only partially paired with a target sequence in a complementary mode, and sequences of the second upstream primer and the probe are the same with the partial sequence, not paired with the target sequence in the complementary mode, on the first upstream primer. The detection method adopts a digital polymerase chain reaction (PCR) method, and pretreatment that a sample is unlinked into single chains is conducted before a conventional digital PCR is conducted. Through the primer composition and the detection method, the detection sensitivity and specificity of EGFR gene mutation can be improved, and the detection cost can be lowered; and the primer composition and the detection method are wide in application range, and the requirement for the DNA content in the sample is extremely low.