  We develop an event mixing technique with a missing mass consistency (MMC)
cut and a pion energy (PE) cut for the measurement of two-pion Bose-Einstein
correlations (BEC) in reactions with only two identical pions produced in the
final state. A multi mixing mode that allows one event to be mixed with
multiple other events is proposed for the purpose of improving the statistics
of mixed samples, and compared with the single mixing mode which requires one
original event can be mixed only once. Numerical tests using the {\gamma}p ->
{\pi}^0 {\pi}^0 p events are used to testify its ability to measure two-pion
correlations. To improve the mixing speed, the optimal MMC cut window is also
explored via simulations.
