We present UBVR_c_I_c_ photometric study of three intermediate age open star clusters NGC381, NGC2360, and Berkeley68 (Be68). We examine the cluster membership of stars using recently released Gaia DR2 proper motions and obtain a total of 116, 332, and 264 member stars in these three clusters. The mean reddening of E(B-V)=0.36+/-0.04, 0.08+/-0.03, and 0.52+/-0.04mag is found in the direction of these clusters where we observe an anomalous reddening towards NGC381. We fitted the solar metallicity isochrones to determine age and distance of the clusters which are found to be log(Age)=8.65+/-0.05, 8.95+/-0.05, and 9.25+/-0.05yr with the respective distance of 957+/-152, 982+/-132, and 2554+/-387pc for the clusters NGC381, NGC2360, and Be68. A two-stage power law in the mass function (MF) slope is observed in the cluster NGC381, however, we observe only a single MF slope in the clusters NGC2360 and Be68. To study a possible spatial variation in the slope of MF, we estimate slopes separately in the inner and the outer regions of these clusters and notice a steeper slope in outer region. The dynamic study of these clusters reveals deficiency of low-mass stars in their inner regions suggesting the mass segregation process in all these clusters. The relaxation times of 48.5, 78.9, and 87.6Myr are obtained for the clusters NGC381, NGC2360, and Be68, respectively, which are well below to their respective ages. This suggests that all the clusters are dynamically relaxed.