A virtual prototype of oblique rotary tilling based on SPH(Smooth Particle Hydrodynamics) was developed. Digital simulation and field test of oblique rotary tilling were conducted. The digital simulation suggested that soil mainly was torn to failure during oblique rotary tilling. Therefore, oblique rotary tilling could save energy. The given power consumption comparison of digital simulation and indoors test verified the virtual prototype. The optimization value of oblique angle and phase angle was given when rotary velocity equals 200rpm and working velocity equals 0.4m/s based on simulation. By simulating throwing soil during rotary tilling, the result suggested that the velocity of soil thrown was not uniform but lean to tangent blade’s direction. This simulation result should be taken into consideration while designing oblique rotary tiller. Furrow bottom shape was figured out by simulating, too. The convex height was about 9.6% of tilling depth. All of the research result suggested that oblique rotary tilling might be a very potential tilling method which could save tilling energy greatly.