Abstract: Toxic effect of phenol, nitrophenol, copper, mercury and zinc on the embryo and larvae were determined with soft water. Expect phenol, the sensitivity of the other four chemicals between loach and other fishes are similar in acute toxicity. During the embryo-larvae toxicity test, larvae stage is more sensitive than embryo stage and the NOEC and LOEC for three five chemicals were: 3.01 ～6.0, 0.56～0.8, 0.0041～0.0087, 0.0975～0.0141, 0.53～1.09mg/L respectively. The sensitivity of phenols to loach was similar to other fishes in EL test but which was different among the three heavy metals. The advantage of loach as a test materiel is only one female can give abundant and fine quality eggs and can save the trouble of the inhomogenous eggs obtained from more than one female while the EL toxicity test is carried out with SIS Method.