An electrothermal oil radiator includes a radiating body (1), an electric-control box (2) mounted on the radiating body (1) and a heating body (3) located inside the radiating body (1). The radiating body (1) includes a plurality of radiating fins (11) linked in turn. Each radiating fin (11) is hollow and sheet-like and has at least two oil leading grooves (12) inside thereof. Hollow connecting sleeves (13) extending horizontally are formed or mounted on upper and lower ends of each radiating fin (11). An oil leading hole in communication with the oil leading grooves (12) is formed in each connecting sleeve (13). The sleeves (13) on each radiating fin (11) are connected together to form a sealed oil cavity in which heat conducting oil is filled. A reinforcing radiating fin (4) is mounted between two adjacent radiating fins (11).