In response to the problem of metal strip wrinkling and fracture caused by uneven heating in current induction heaters, this paper designs an induction heater that can uniformly induce heating of ultra-thin metal strips. Considering the uniform distribution of magnetic flux, the distance between adjacent coils of the heater is designed. Based on the end effect of metal strip, the bending angle of the edge coil of the heater is derived and calculated. The calculation results are analyzed and verified through simulation. The results show that when the longitudinal size of the induction heater is the smallest, the surface temperature uniformity of the metal strip reaches 92%.