We present a theoretical study of quasi-classical transport of two-dimensional Bloch electrons under the influence of an electric and a magnetic fields, starting respectively from the quasi-classical equation of motion of electrons and from the balance equations proposed by one of the authors. The electron longitudinal velocity vx and the Hall drift velocity vy are calculated as functions of the magnetic field under different strengths of the applied electric field. It is shown that both vx and vy always change continuously with variation of magnetic field. No sudden jump in the vx-B or the vy-B curve has been found at any given electric field, in contradiction with the claim made in a recent paper published in Acta Physica Sinica (vol. 46). The possible cause for this disagreement is discussed. Furthermore, we point out that the validity of the naive way to study electron transport by directly introducing a damping force into the quasi-classical equation of motion of electron is quite limited.