Influence factors on the effect of equivalent circuit parameters of longitudinal vibration piezoelectric transformers at the second harmonic was studied.Piezoelectric transformers of different design and crafts were produced using the lead zirconate titanate ceramic,and its equivalent circuit parameters were multiple measured. The error estimation between measurements and calculations showed that some factors, e.g. the area of electrode covered, the electrode leads position,and the connection point size would greatly influence the equivalent circuit parameters. The results provided a reliable basis for actual production and testing of a piezoelectric transformer.