  A model was constructed to explain the orbit modulation of PSR J0737-3039B
(referred to as B), which included the following suppositions: (1) B has
arrived at the aged period and generally cannot emit observable light; (2) The
PSR J0737-3039A (referred to as A) is dynamic and is encircled by dense charged
particles. When A revolves along its orbit, some of the particles are scattered
and form a particle cloud band along its orbit; (3) When passing the two
intersection points of the orbits, B goes through the cloud band and drives the
cloud particles to emit light; (4) Generally, B passes twice through the cloud
band every orbit cycle; hence, there are two bright phases along the orbit. (5)
It is the complexities of the distribution of the cloud particles and B's
emission region that cause the bright phases to drift away from the orbit
intersections. We also provide two predictions for the coming performance of B
to test our model.
