The invention discloses 3D (three dimensional) printing equipment for preparing a thermoplastic elastomer product, which mainly consists of a material melting and conveying unit, a material squeezing unit, a three-dimensional coordinate platform and a rack; in the material squeezing unit, a valve body is full of melted and plasticized materials through a hot runner; the opening and closing of the nozzle of the valve body is controlled by a valve needle; the valve needle is fixed onto a thermal insulator which has certain elastic deformation capability and thermal insulation capability; corresponding force is applied to the upper side of the thermal insulator by using a spring and an electromagnet, so as to enable pressure generated by the melted materials in the valve body to be balanced with the applied force, so that the valve needle can seal the nozzle, and when the electromagnet is controlled to intermittently move up and down according to certain rules by a controller, the valve needle also moves up and down correspondingly due to the fact that the balance of the force is broken, so that the nozzle is continuously opened and closed to form micro droplets; micro droplets are cooled and formed on the three-dimensional platform, and the product is finally printed. According to the equipment disclosed by the invention, different materials of micro droplets or fuses can be sprayed according to different time sequences, and the product, which is made from a soft and hard composite material and has multifunctional gradients, can be printed.