This paper described on relation between the catches of tuna and the distribution of water temperature of eastern fishing ground of Tropical region in the Pacific Ocean. The data of catches and water temperature used in this paper were based log book which # 27 CHENG RONG(Gross tonnage : 399 ton) had been worked eastern fishing ground(Lat : 09$^{circ}$N- 14$^{circ}$S, Long : 115$^{circ}$- 149$^{circ}$W)from January to October, 1991. The obtained result are as follows : 1. On the relation between the catches and the geographical distribution, bigeye tuna was higher catches at Lat 4$^{circ}$- 9$^{circ}$N, Long 135$^{circ}$- 139$^{circ}$W area in the equatorial counter current region where surface water temperature was range of 27.5$^{circ}C$ to 27.9$^{circ}C$, yellowfin tuna was higher catches at Lat 4$^{circ}$- 9$^{circ}$S, Long 145$^{circ}$- 149$^{circ}$W in the south equatorial current region where surface water temperature was range of 28.$0^{circ}C$ to 28.4$^{circ}C$ and albacore tuna was higher catches at Lat 10$^{circ}$- 14$^{circ}$S, Long 120$^{circ}$- 124$^{circ}$W area in the south equatorial current region where surface temperature was range of 26.5$^{circ}C$ to 26.9$^{circ}C$ 2. On the relation between catches and distribution of vertical water temperature, bigeye tuna was higher catches at the water temperature of 1$0^{circ}C$ to 12$^{circ}C$ on depth layer between 300m and 360m, yellowfin tuna was higher catches at the water temperature of 15$^{circ}C$ to 19$^{circ}C$ on depth layer between 180m and 280m and albacore tuna was higher catches at the water temperature of 12$^{circ}C$ to 14$^{circ}C$ on depth layer between 280m and 310m. Above the result, it seemed that bigeye tuna distributed deeper layer than yellowfin and albacore tuna.