Abstract: Combining with a measurement of velocity by photoelectric technology, rebuilding a type of nail gun used in civil engineering, a more simple, reliable and miniaturized measurer for shockwave velocity was developed. Thus, the difficult problem to predict the consistency and reliability of self-triggering coaxial detector for shockwave velocity was solved under lower shock pressure. The experimental results indicate that the impact velocity induced by a steel projectile with the statistical weight, (25.50.1) g, is 226.2 m/s; the reliability is larger than 66.67%, and the coherency, represented by standard error, is less than 1.14%, predicted by test results for 6 detectors, being part of a group of product. It provides an effective technique for measuring detonation and shock compression.