  Assuming that the e-folding number is just determined by the change of the
scale factor, the tachyonic inflation theory in LQC has been discussed.
Considering the tachyon field with exponential potential and inverse quadratic
potential, we find that the evolutionary pictures of super inflation are
affected by the potentials and the initial conditions. However it cannot
provide enough e-folding number, no matter which condition is chosen. Therefore
a slow-rolling inflation is necessary. The e-folding number for slow-rolling
inflation depends on the values of the parameter $\alpha$ of the exponential
potential and the initial conditions. To get enough e-folding number, $\alpha$
should be small. Based on the slow-rolling inflation happens immediately when
the super inflation ends, and the scale factor is continuously growing during
the whole inflation stage, we consider an e-folding number provided by the
whole inflationary stage, and we find that it is easier to get enough e-folding
number when the scale factor increases during all the inflation phase.
