Transverse Zeeman slower composed of an array of permanent magnets is investigated for Sr optical clock. We calculated the magnetic field distribution of 88 Sr atoms based on experimental condition, achieving a reduction of the velocity of atoms from 410 m/s to 50 m/s. The atoms flux through the transverse magnetic field was 7.9×105. Such permanent Zeeman slower needs no high currents or water cooling and the spatial distribution of its magnetic field can be adjusted. Another advantage of this Zeeman slower is its small size and high reliability. Therefore, a miniature Zeeman slower can be attained.