We investigate some aspects of Galactic disc kinematics based on the data on open clusters from the current version of “The Homogeneous Catalog of the Main Parameters of Open Star Clusters” and from Gaia DR2. Based on the radial velocity and proper motion data for the clusters we determine the angular velocity of the Sun in the Galaxy as Q0 = 25.6 ± 1.2 kms-1 kpc-1. A new approximation of the Galactic rotation curve by a polynomial in inverse powers of galactocentric distances is constructed. We consider the influence of spiral density waves on the smoothed velocity field of the Galactic disc. The radial fR = 4.6 ± 0.7 kms-1 and tangential fe = 1.1 ± 0.4 kms-1 amplitudes of the velocity field distortion are estimated from the radial dependences of the residual spatial velocity components of the clusters.