In order to study the influence of journal surface errors on the system characteristics of sliding bearing rotor and the feasibility of the SDT error model based on SDT theory,the SDT theory was introduced to characterize the random errors on journal surface.A new generalized equation for calculating oil film thickness was further derived.On the basis of the equation,the Reynolds equation was solved.Based on the SDT error model,the influence of roundness error on the frictional power loss,critical speed,bearing capacity and stability of sliding bearings was studied.The results show that with the increase of the spinor parameters,the friction power loss decreases in x direction and increases in y direction.The friction power loss decreases with the increase of the eccentricity,especially when the eccentricity ratio is less than 0.5.The above shows that changing the spinor parameters size in different direction,the influences of the roundness error on the friction power loss are different.At the same time,with the increase of the spinor parameter,the critical speed of the system increases,especially when the eccentricity is greater than 0.6.Moreover,it has a promoting effect on the stability of the system,and the promoting effect is more obvious when the eccentricity is greater than 0.5.Therefore,it not only proves the feasibility of the SDT error model,but also provides reference for tolerance selection in bearing design.