As the most commonly used antipyretic and analgesic drug,paracetamol(PA)coexists with neuro-transmitter dopamine(DA)in real biological samples.Their simultaneous determination is extremely important for human health,but they also interfere with each other.In order to improve the conductivity,adsorption affinity,sensitivity,and selectivity of TiO2-based electrochemical sensor,N-doped carbon@-TiO2 double-shelled hollow sphere(H-C/N@TiO2)is designed and synthesized by simple alcoholic and hydrothermal method,using polystyrene sphere(PS)as a template.Meanwhile,TiO2 hollow spheres(H-TiO2)or N-doped carbon hollow spheres(H-C/N)are also prepared by the same method.H-C/N@TiO2 has good conductivity,charge separation,and the highly enhanced and stable current responses for the detection of PA and DA.The detection limit and linear range are 50.0 nmol/L and 0.3-50 μmol/L for PA,40.0 nmol/L and 0.3-50 μmol/L for DA,respectively,which are better than those of carbon-based sen-sors.Moreover,this electrochemical sensor,with high selectivity,strong anti-interference,high reli-ability,and long time durability,can be used for the simultaneous detection of PA and DA in human blood serum and saliva.The high electrochemical performance of H-C/N@TiO2 is attributed to the multi-functional combination of different layers,because of good conductivity,absorption and electrons transfer ability from in-situ N-doped carbon and electrocatalytic activity from TiO2.