Preparation method for high voltage LED chip

The invention provides a preparation method for a high voltage LED chip. The method mainly comprises the steps of combining with a second substrate by a wafer bonding manner; peeling off a first substrate and a buffer layer to expose an N type GaN layer; forming a plurality of second trenches in a partial region of the N type GaN layer to form GaN micro-crystals arranged at intervals; forming a groove in a partial region of the GaN micro-crystals, wherein the groove is communicated with the second trenches, and the groove reaches a reflective metal layer measured based on the depth of the groove; depositing a second insulating layer on the side wall of the GaN micro-crystals of the second trenches; depositing metals on the N type GaN layer, partial exposed reflective metal layer, the second trenches and the surface of the second insulating layer to form an N electrode, a P electrode and an interlinking metal layer connected with the adjacent LED electrodes to form a plurality of interconnecting LEDs. The preparation method for the chip is simple and the preparation method can be driven by higher voltage; in a control circuit for a lamp, a transformer is not required, so that the production cost is reduced; and in addition, the high voltage chip is free from current crowding, capable of passing high current and good in the heat dissipation performance.