Zhang is a person whom Kangxi especially trusts, and he will discuss many things with Zhang. Even when he wanted to make Mei the heir to the throne, he didn't hide Zhang, so he wrote the imperial edict in front of him and gave it to Zhang for safekeeping.

Zhang is a Han nationality. Under the rule of the Manchu Dynasty, the status of Han officials was very low, but Zhang was valued by the emperor after three dynasties. This is because of his loyalty, intelligence and diligence, he didn't join any group. In his later years, Emperor Kangxi was particularly worried that his official position would be sealed up by Jiuzi. He wants to find a prince who is really capable of assuming the responsibility of heir, but there are many calculations between princes, and he is particularly embarrassed by cronyism in the court. He doesn't know who to discuss with. The prince sold the official, and the four princes went south to Yangzhou to provide disaster relief, but failed to recover the debts owed by the household department, and some dignitaries ran around. Eight emperors entered the palace to take an examination of Kangxi, so they handed the passbook to Zhang who was on the night shift. Zhang directly burned the passbook and said that he had never seen any memorial at all. In this way, he expressed himself and did not join any party.

Emperor Kangxi was particularly satisfied with Zhang's practice. After hunting, he took Zhang with him, but the prince defected and Emperor Kangxi suddenly fell ill. Zhang, who was also frightened, strengthened his mind and gave orders to Emperor Kangxi, pointing out that the prince was plotting to save Emperor Kangxi, which made Emperor Kangxi trust Zhang more. After Emperor Kangxi succeeded to the throne, when there were only four emperors and eight emperors left, Zhang would observe and judge the situation, help Emperor Kangxi make a choice, and make Zhang the biggest confidant of Emperor Kangxi. Zhang was appointed as the position of the records of the upper study.

Zhang's attitude towards the imperial court and political situation made Kangxi particularly satisfied. Moreover, he is a Han Chinese, and even if he holds the greatest power, he can only be a courtier. Therefore, Emperor Kangxi trusted him very much, and almost everything would be discussed with Zhang. If the fourth emperor was chosen as the next emperor, he would not hide it from him.