Taking J.regia "Wen 185" in Wensu County and Yecheng County as the research objects, the change law of walnut fruit quality and green fruit cracking rate in different sampling periods was studied, and the suitable sampling period of "Wen 185" in Wensu County and Yecheng County was determined.The result shows:（1）With the delay of the harvesting time of J.regia "Wen 185" The rate and shell thickness gradually increased, tends to be stable during harvest VII, water content and shell thickness gradually decrease in Wensu and Yecheng County. The green fruit color gradually changed from dark green to yellow-green and the surface fluff was reduced, the green skin (involucral bud) cracked on the fruits from the harvesting stage II, and the cracking rate of the green skin of the fruits in the harvesting stage VII reached about 65% and 75% respectively. The color of the seed coat of the nucleolus gradually changes from light white to milky white, yellow white and yellow to light yellow brown at the harvesting stage VII, The color of the nucleolus gradually changed from milky white to yellowish white, and the nucleolus tended to be plump. （2）The nucleolar fat content of Wensu and Yecheng County J.regia "Wen 185" accumulated rapidly during sampling period I to VI, this is a critical period for fruit fat accumulation. Protein, vitamin C and Zn increased gradually, soluble sugar increased, decreased, increased, K and Ca decreased and then increased significantly, and tended to be stable during harvest period VII.（3）Comprehensive evaluation Wensu County J.regia "Wen 185"had the highest comprehensive evaluation score in the harvesting time VI, and Yecheng County J.regia "Wen 185" had the highest comprehensive evaluation score in the harvesting time VII, and the relationship between green fruit cracking rate and walnut quality is clarified. the cracking rate of the green peel of the fruit can be used as an important basis for judging that the J.regia "Wen 185" in Wensu and Yecheng County have entered the suitable harvesting time. The green fruit cracking rate of J.regia "Wen 185" in Wensu reached about 65%, and J.regia "Wen 185" in Yecheng County began to enter the suitable harvesting time at about 75%. Key words: walnut; cracking rate of green walnut; quality evaluation; appropriate harvesting times.