Abstract: Flux of X-ray produced from focussing laser radiation onto solid target was measured using a Ross filter system. The system consists of two identical X-ray detectors, appropriate filters mounted ahead of each detector. Ross filter method uses the advantages of the X-ray nuclide adjacent similar rejection, can filter out a narrow-band interference and remove high-energy part of the plane to get the Ti target K-shell X-ray radiation yield. Experiment result shows that k-shell emission of 4.5-4.9 keV prevails over continuum spectra (coincidence with result from crystal spectrometer). Characteristic emission increases with increased laser energy and a peak in conversion efficiency appears near 21015 W/cm2.