The dynamic concentrations of glucose, fructose, sucrose and total sugar were determined through exogenous ABA and GA3 treatments during young period of fruit and before fruit coloring in pulp of ‘Cara cara’ navel orange. The results are as fol ows： 10 mg/L ABA increased glucose, fructose and total sugar concen-tration significantly or very significantly, ABA treatment of 50 mg/L increased sucrose concentration very significantly, but ABA treatment of 100 mg/L decreased glucose concentration very significantly. GA3 treatment of lower and middle concentrations（10, 50 and 250 mg/L） increased sucrose concentration very significantly, GA3 treatment of 10 mg/L had no remarkable effect on glucose and fructose concentration but in-creased total sugar concentration very significantly, GA3 treatment of 50, 250 and 500 mg/L decreased glucose, fructose and total sugar concentration very significant-ly. Therefore, ABA treatment of lower concentration could increase one or several kinds of sugar concentration, but GA3 treatment of higher concentration （250 and 500 mg/L） restrained sugar concentration in pulp of ‘Cara cara’ navel orange seri-ously.
