Ultrafine WC-Ni cemented carbides were manufactured by coupled multi-physical fields activated technology to study the effect of the Ni content to sintering of WC-Ni cement carbide. It was found that multi-physical fields activated technology is an effective method to manufacture WC-Ni cemented carbide, and when the content of Ni increased, the micro pore diminished, and densification of the samples increased, but the particle size of WC increased. In addition, firstly, the Micro hardness increases quickly and then decrease with the increasing of the Ni content. At the same time, the fracture toughness (KIC) increase sharply to 8.5 MPa.m1/2 with the increase of the Ni content.