The distance measurements of supernova remnants in the fourth Galactic quadrant

We take advantage of red clump stars to build the relation of the optical extinction (A(V)) and distance in each direction of supernova remnants (SNRs) with known extinction in the fourth Galactic quadrant. The distances of nine SNRs are determined well by this method. Their uncertainties range from 10% to 30%. which are significantly improved for eight SNRs. G279.01-1.1. G284.3-1.8. G296.1-0.5. G299.2-2.9. G308.4-1.4, G309.2-0.6, G309.8-2.6 and G332.4-0.4. In addition, SNR G284.3-1.8 with the new distance of 5.5 kpc is not likely associated with the PSR J1016-5857 at 3 kpc.