Adopted the compounding Ni-base alloy powder and properly mixed a few functional powders, the study on surface strengthening for slab crystallizer base material by substrate pre-heated and laser coaxial feeding cladding was investigated. The results indicate that the laser coaxial feeding cladding can effectively decrease cladding layer’s pores and crackers compared with laser pre-laid cladding, the cladding layer structure is compact, uniform with typical rapid freezing character and the structure can be controlled by compounding alloy powders. The elements of substrate and cladding layer infiltrate and dilute to each other, the bonding interface is good with metallurgic and tight combination and the rate of dilution is very low. The erosion resistance and thermal fatigue of substrate are improved evidently by this treatment.