Thirty years of effort in semiconductor quantum dots has resulted in significant developments in the control of spin quantum bits(qubits).The natural two-energy level of spin states provides a path toward quantum information process-ing.In particular,the experimental implementation of spin control with high fidelity provides the possibility of realizing quantum computing.In this review,we will discuss the basic elements of spin qubits in semiconductor quantum dots and summarize some important experiments that have demonstrated the direct manipulation of spin states with an applied electric field and/or magnetic field.The results of recent experiments on spin qubits reveal a bright future for quantum information processing.