The utility model discloses a combustor and water heater that has it, wherein the combustor includes: the fire is arranged, it has mixed air cavity to prescribe a limit to in the fire is arranged, the fire is arranged to have and mixes the air inlet that the air cavity switched on, first burner, the second goes out burner and third play burner, first burner, second play burner and third play burner be spaced apart arranging in proper order, the fire is arranged still has air inlet duct, air inlet duct arranges with the air inlet is spaced apart, air inlet duct switches on through first wind channel with first burner, air inlet duct and second play burner switch on through the second wind channel, mix between air cavity and the first wind channel and to switch on through the third wind channel. According to the utility model discloses a combustor, first wind channel possess and draw the function of penetrating the air mixture in the third wind channel, can effectual control gas flow distribution, and every fire in rows becomes deep or light dense play fire mode, light flame in the middle of the dense flame that is located both sides can stably be located to reach the control mesh that nitrogen oxide discharged in the flue gas.