Dynamic accuracy appraisal method of optical theodolite, called ‘Hard method’, is rough and complex in engineering. Its appraisal result is inaccurate, poor in reliability and imperfect. For these reasons, a convenient dynamic accuracy appraisal method of optical theodolite is proposed, called ‘Soft method’. Its mathematical model and solution method are deduced. Through simulation, comparative calculation with these two appraisal methods is carried out. The results show that for dynamic accuracy appraisal of optical theodolite, ‘Soft method’ takes greater advantages in accuracy and reliability. In addition, the method is easier and more conducive to engineering applications.