A novel spiral nozzle with involute atomization surface was presented. The spray surface was design as inside and outside conic gradual change helix angle helicoids, which made the stress of the nozzle more uniform. Also it overcame the shortcomings of atomization overlap for traditional spiral nozzle. According to the requirements of involute atomization instead of homocentric circles atomization, the beginning and the end of the involute has been optimized. Then the dynamic and static coordinates were employed to deduce the space geometry model of spray helicoids. At last the model was simulated by using Matlab. The results validated the effectiveness of the proposed geometry model, which provided the theoretic basis for designing and manufacturing the spiral nozzles.