Objective To verify the accuracy of the results of special visual measurement instruments for heterphoric testing. Methods In this cross-sectional study， fifty healthy students served as subjects. The degree of heterphoria was measured by a special visual measurement instrument， the Maddox rod and a synoptophore. A one-way ANOVA and paired t test were used to calculate the data. Results ①The Maddox rod and synoptophore measured the highest amounts of esophoria， accounting for 38% and 34%； hyperphoria was the least， accounting for 2% and 4%. Measurements with the special visual measurement instrument found the highest amounts of esophoria plus hyperphoria， accounting for 36%； orthophoria was found the least， accounting for 4%. ②Esophoria values measured in order from the most to the least were the Maddox rod， measurement instrument and synoptophore （F=3.18， P<0.05）. There was a significant difference between the Maddox rod and synoptophore （P<0.05）， but there were no significant differences between the Maddox rod and measurement instrument and the measurement instrument and the synoptophore （P>0.05）. Exophoria values measured from high to low were the Maddox， synoptophore and inspection instrument. There were no significant differences among the three methods （F=0.83， P>0.05）. Hyperphoria values measured from high to low were the measurement instrument， Maddox rod and synoptophore （F=6.34， P<0.05）. There were significant differences between the measurement instrument and synoptophore and the Maddox rod and synoptophore （P<0.05）， but there was no significant difference between the measurement instrument and Maddox rod （P>0.05）. ③The dominant eye′s value was higher than the nondominant eye′s in esophoria， exophoria and hyperphoria， but only the Maddox rod measured a significant difference in esophoria （t=2.74， P<0.01）. Conclusion There were differences in the degree of heterphoria measured by the three instruments， but there was no significant difference between the measurement instrument and Maddox rod.