  We study the feasibility to observe sterile neutrino at the high energy
colliders with direct production channels through $e^+e^-$, $ep$ collision, and
indirect production channels through decays of heavy meson, baryon and Higgs.
For $e^+e^-$ collision, the $e^+e^-\to\bar{\nu}_e N$ channel is explored with
new signal selection method which tends to be efficient for light $m_N$, the
constraints of active-sterile mixing $|U_{eN}|^2$ at the SuperKEKB, CEPC and
ILC are expected to reach better lower limits than current experiments. For
$ep$ collision, We investigate the heavy sterile neutrino production through a
new channel via proton bremsstrahlung, i.e., $e^-\gamma \to NW^-$, hundreds of
GeV heavy sterile neutrino can be probe and new limit on mixing is given. For
heavy hadrons decay, the lepton-number-violating decays of $\Lambda_c,\
\Xi_{c},\ \Xi_{cc}$ and $\Lambda_b$ are explored via an intermediate on-shell
Majorana neutrino in GeV scale. The branching fractions and the constraints for
$|U_{\ell N}|^2$ are given, and hence may put new limits on this mass region.
The ${\rm Higgs} \to W\mu\mu\pi$ channel is also considered to test massive
neutrino within Higgs sector.
