A variable geometry turbo system that controls a flow of exhaust gas introduced into a turbine of a turbo charger, the system comprising: a vane base ring in which the turbine is positioned at a center thereof; a fixed vane which is fixed onto a first surface of the vane base ring to guide the exhaust gas introduced into the turbine; a variable vane which is pivotally positioned on the first surface of the vane base ring and adjacent to the fixed vane so as to vary a flow path of the exhaust gas introduced into the turbine; a vane cover ring fixed to the vane base ring with the fixed vane and the variable vane interposed therebetween; and an actuating module coupled to the variable vane and selectively actuating the variable vane, a variable pin which is formed at a portion where the variable vane and the fixed vane are engaged with each other, wherein a convex curved surface is formed on an outer end of the variable vane to correspond to an outer circumference of the variable pin, wherein a concave curved surface is formed on an inner end of the fixed vane to correspond to the convex curved surface, and wherein an insertion hole is formed in the vane base ring, into which the variable pin is inserted, wherein the fixed vane is formed to be concavely curved toward the turbine, wherein the variable pin is disposed in a middle of the vane base ring in a radial direction of the vane base ring, characterized in that the fixed vane and the variable vane are linearly aligned at the variable pin when the variable vane is rotated toward the turbine, and the fixed vane and the variable vane form a bent angle with respect to each other at the variable pin when the variable vane is fully rotated distally from the turbine, and the fixed vane extends between its inner end and an outer end thereof, which is opposite to the inner end of the fixed vane, in a manner that the fixed vane extends, starting from its outer end, with a concave curvature, which is curved toward the turbine, until a middle portion of the fixed vane and then the concave curvature transitions into a convex curvature, which is curved away from the turbine, such that the fixed vane further extends from the middle portion to the inner end of the fixed vane with said convex curvature, whereby the fixed vane forms an elongated S-form between the outer end and the inner end of the fixed vane. a vane base ring in which the turbine is positioned at a center thereof; a fixed vane which is fixed onto a first surface of the vane base ring to guide the exhaust gas introduced into the turbine; a variable vane which is pivotally positioned on the first surface of the vane base ring and adjacent to the fixed vane so as to vary a flow path of the exhaust gas introduced into the turbine; a vane cover ring fixed to the vane base ring with the fixed vane and the variable vane interposed therebetween; and an actuating module coupled to the variable vane and selectively actuating the variable vane, a variable pin which is formed at a portion where the variable vane and the fixed vane are engaged with each other, wherein a convex curved surface is formed on an outer end of the variable vane to correspond to an outer circumference of the variable pin, wherein a concave curved surface is formed on an inner end of the fixed vane to correspond to the convex curved surface, and wherein an insertion hole is formed in the vane base ring, into which the variable pin is inserted, wherein the fixed vane is formed to be concavely curved toward the turbine, wherein the variable pin is disposed in a middle of the vane base ring in a radial direction of the vane base ring, characterized in that the fixed vane and the variable vane are linearly aligned at the variable pin when the variable vane is rotated toward the turbine, and the fixed vane and the variable vane form a bent angle with respect to each other at the variable pin when the variable vane is fully rotated distally from the turbine, and the fixed vane extends between its inner end and an outer end thereof, which is opposite to the inner end of the fixed vane, in a manner that the fixed vane extends, starting from its outer end, with a concave curvature, which is curved toward the turbine, until a middle portion of the fixed vane and then the concave curvature transitions into a convex curvature, which is curved away from the turbine, such that the fixed vane further extends from the middle portion to the inner end of the fixed vane with said convex curvature, whereby the fixed vane forms an elongated S-form between the outer end and the inner end of the fixed vane.