  The J-PARC muon g-2/EDM experiment aims to measure the muon magnetic moment
anomaly $a_{\mu} = (g -2 ) / 2 ~ $. The target sensitivity for $a_{\mu}$ is a
statistical uncertainty of $450 \times 10^{-9}$, and $a_{\mu}$ can be extracted
by measuring the spin precession of muons ($\omega_a$). The $\omega_a$ can be
extracted from the distribution of muon decay time, and the time is measured by
reconstructing tracks of positrons which are decayed from the muons. To extract
$\omega_a$ precisely, the systematic effects on $\omega_a$ should be controlled
under the aforementioned sensitivity. To study systematic effects, we develop a
compact simulation package, and using our developed package, we study several
systematic effects and discuss results. We discuss the package details and
studies of systematic effects on $\omega_a$ based on our package.
