Optical clock is reported that the capture of cold strontium (Sr) atoms in a magneto-optical trap (MOT) by using Zeeman slowing. The MOT is loaded from a thermal atomic beam which is decelerated by a Zeeman slower having 10.2 A electric current. The anti-Helmholtz coils of MOT have 10 A current and then can induce a linear magnetic field. Its gradient is 4 mT/cm in the central zone. The 461 nm laser is used for Zeeman slowing and trapping which corresponds to the transition of Sr atomic level (5s2)1S0→(5s5p)1P1 . According to the experiment,four isotopes of Sr in MOT are obtained and the fluorescent spectrums of the atoms are detected. Using the fluorescence,the number of three isotopes 88Sr,87Sr ,86Sr is measured,which is 1.759×106,1.759×105 and 2.638×105 separately.