A solution cathode glow discharge plasma-atomic emission spectrum apparatus and method capable of performing direct gas sample introduction and used for detecting a heavy metal element. The solution cathode glow discharge plasma-atomic emission spectrum apparatus comprises a high-voltage power source, a ballast resistor, a hollow metal anode and a solution cathode. The hollow metal anode is connected to a positive electrode of the high-voltage power source by means of the ballast resistor, and the solution cathode is connected to a negative electrode of the high-voltage power source by means of a graphite electrode. The plasma apparatus is further configured in such a manner that a discharge region is formed between the hollow metal anode (10) and the solution cathode, and the hollow metal anode further serves as a sample introduction pipeline, so that gas to be detected enters the discharge region and is excited.