The invention discloses a high voltage JFET device and a processing method of the same. A P substrate is provided with a deep N-well. From a cutaway view angle, a field oxide is on the deep N-well, and the two ends of the field oxide are a JFET source area and a drain area. The field oxide is covered with a poly-silicon field plate. The deep N-well is divided into two sections: a first deep N-well section and a second deep N-well section wherein the first deep N-well section contains the JFET source area and the second deep N-well section contains the JFET drain area and a P injection layer. The first deep N-well section and the second deep N-well section are independent from each other. Between the first deep N-well section and the second deep N-well section is a P-well. The P-well shares the sizes with both the two deep N-well sections. Also between the first deep N-well section and the second deep N-well section is the P injection layer. The P injection layer, right under the P well, also shares sizes with with both the two deep N-well sections. The JFET device provided by the invention is provided with adjustable pinch-off voltage and at the same time, with high breakdown voltage as well. The invention also discloses a processing method for such a high voltage JFET device.