The observations of gravitational wave (GW) radiation opened a new window on our understanding of the universe. In this talk, we will introduce the detectability of different continuous GW sources including ultra-compact X-ray binaries, AM CVn stars, compact intermediate-mass black-hole X-ray binaries by the space GW detectors like LISA. We also discuss the significance of compact binary pulsars as dual-line GW sources on the constraint for the equation of state of neutron stars.