Speed and position detection system is the basis of propulsion and traction control for high speed maglev train. Compared with traditional railways, high speed maglev trains have some exclusive problems which can affect system proper working, such as levitating fluctuation, joint gap of long stator track and contactless reader for absolute position. To reduce detection error of relative position due to levitating fluctuation, a method utilizing levitation gap to normalize detection output into the one of 8mm levitation gap is proposed. It is found that it can satisfy the precision requirement of 2.8°for relative position detection. To reduce detection error of relative position due to joint gap of track, a switching method between two relative-position detections based on a predictive adaptive filter was adopted. As a result, it can avoid distortion and satisfy the precision requirement of relative position detection. To solve the problem of absolute position reader by contactless method, an equivalent model of electro-magnetic induction reader was analyzed. It is found that the frequency and amplitude of magnetic fields need be increased and the resistor of emit coils need be decreased. As a result, it can satisfy the absolute position detection requirement.