Forming methods of one-piece weldless wheels made of metal sheets including the steps of rolling, forming a primary wheel rim and a primary wheel disc, roll forming, compressing and shaping, in order to obtain one-piece weldless wheels. The methods can form weldless wheels by rolling, cold roll forming and cold extruding, which can reduce energy consumption by 45-55% and cut down material cost by 5-15% while improving strength of the wheel by 20-30%. A wheel with different thicknesses can be formed by the methods and can meet the requirements on mechanical strength. The methods can improve the precision of the wheel and minimize the swing value and jerk value. The wheel produced is safer, and the regular air tight test on the wheel is not necessary.