Since the approval of micuronium chloride in 1992 , cases of prolonged neuromuscular block caused by micuronium chloride in patients with plasma cholinesterase deficiency have been reported. As early as 1991, studies have confirmed that the use of micuronium chloride in patients with pseudocholinesterase deficiency can prolong the duration of neuromuscular block , but the earliest cases of unexpected long-term neuromuscular block can be traced back to 1993 . According to the incidence of homozygote of atypical mutation (A mutation) of pseudocholinesterase gene in Caucasians (1/3000-1/2500) , it is estimated that the actual occurrence of cases is far more than that of reported cases, while homozygote mutation of cholinesterase gene is rare in Oriental people . At present, there are few relevant studies and reports in China, so more case reports and studies are necessary, which will help to enhance anesthesiologists' understanding and attention to patients with cholinesterase deficiency and avoid serious consequences.