For the first time, a deep learning (DL) algorithm is presented to study the effect of the source of variability on the performance of semiconductor nanodevice. This paper reports the possibility of an alternative solution of device simulation in order to optimize the source variation. It is based on the statistical distribution of work function fluctuation (WKF) on the metal gate depending on the orientation and location of metal grains. It has been revealed that the WKF of a metal gate can lead to different fluctuations in electrical characteristics. Therefore, an emerging DL algorithm, artificial neural network (ANN) is utilized to identify the appropriate WKF patterns on the metal gate that can reduce the impact of characteristic fluctuation, i.e., σVTH, σION and σIOFF, simultaneously. The application of the DL-ANN algorithm to multichannel gate-all-around silicon nanosheet MOSFETs is explored to suppress the effect of WKF on the characteristic fluctuation. Consequently, it can be further utilized to investigate the implication of WKF for the process variation, modeling the nanodevices and analysis of circuit design. Notably, this technique can be extended to study the diverse random sources and process variation effects for emerging nano-CMOS devices and can effectively accelerate the device simulation and optimization.