Abstract: In order to explore the application of pea starch in industry, a new preparation process of etherified pea starch was studied in this paper. The hydroxypropyl-carboxymethyl pea starch was prepared by a stepwise continuous reaction method using sodium hydroxide (NaOH) as a catalyst, monochloroacetic acid (MCA) and propylene oxide as the etherification agent in an ethanol solvent. The optimal reaction conditions for the hydroxypropylation and carboxymethylation of pea starch were determined through a single factor and orthogonal experiment with hydroxypropylation degree, carboxymethyl degree and reaction rate as indexes. The optimal parameters in hydroxylpropyl reaction were sodium hydroxide dosage (1%, 2%, 3%, 4%, 5%), mass fraction of starch milk (25%, 30%, 35%, 40%, 45%), propylene oxide dosage (5%, 10%, 15%, 20%, 25%), reaction time (8 h, 12 h, 16 h, 20 h, 24 h) and reaction temperature (35℃, 40℃, 45℃, 50℃, 55℃). The optimal parameters in carboxymethylation reaction were monochloroacetic acid to starch material molar ratio (1.0, 1.5, 2.0, 2.5, 3.0), sodium hydroxide to starch material molar ratio (2.75, 3.25, 3.75, 4.25, 4.75), reaction time (1 h, 2 h, 3 h, 4 h, 5 h), reaction temperature (45℃, 50℃, 55℃, 60℃, 65℃). According to the single factor test results, orthogonal test was carried out to determine the optimal preparation process. The optimized conditions of the hydroxypropylation was 40% of the starch concentration, 5.5% of NaOH (starch dry basis mass), 23% of the propylene oxide (starch dry basis), and the reaction time 16 h at 60℃. The optimal reaction conditions for the carboxymethylation was the molar ratio of NaOH to AGU of 3.25, the molar ratio of MCA to AGU of 1, and 5 h reaction time at 60℃. The hydroxypropylation degree, carboxymethyl degree and reaction rate of the optimized product were up to 0.197 9, 0.780 2 and 78.02%, respectively. The results showed that the process performed a high degree of etherification and efficiency, and low energy consumption and cost in industrial production.