Experimental investigation has been carried out to study the interaction between incident shock-wave and turbulent boundary layer near an expansion corner at a free stream Mach number of 3.9. The wedge angle (α), expansion angle (β) and the distance of inviscid impingement location (X) from the expansion corner were varied. Fin induced vortex dominated side wall flow was found to affect the complex interaction and make the interaction three dimensional which otherwise would be two dimensional. The line of separation is found to be independent of expansion corner angle even for the impingement downstream of expansion corner. With increase in wedge angle, the line of separation moves upstream. Peak pressure reduces with downstream impingement location and increase in expansion corner angle. Pressure far downstream of the interaction region is found to be nearly same irrespective of the configurations.