  The Orthogonal Polarization Modes (OPM) have been reported observationally
and accepted widely by pulsar researchers. However, no acceptable theory can
show the origin of the OPM, which becomes a mystery in pulsar research field.
Here a possible way to solve this mystery is presented. We ask a question: Does
there exist any real so-called OPM in pulsar radiation? It is proposed in this
paper that the `observed OPM' in individual pulses could be the results of
depolarization of pulsar radiation and the observational uncertainties
originated from polarimeter in observation. A possible way to check this idea
is suggested. If the idea is verified, the pulsar research would be influenced
significantly in theory and in observation.
