The work aims to investigate the causes of dummy plating in palladium plating process by electrochemical methods and explore the electrochemical relationship behind the dummy plating.The initiation process of electroless palladium plating was probed by the electrochemical open-circuit potential, and the linear scanning voltammetry was taken to measure polarization curves. During measurement of anodic polarization curve, palladium salt was not added, while during measurement of cathodic polarization curve, sodium hypophosphite was not added. The onset oxidation potential of sodium hypophosphite (EO) and the onset reduction potential of palladium ion (ER) with temperature, as well as the effect of glycine concentration on EO and ER, were determined respectively by linear scanning voltammetry. In addition, the relationship between the variation of palladium layer thickness and glycine concentration was also investigated by electroless plating experiments. It was found that there was a difference in the rapidity of initiating palladium deposition between the first use and multiple uses of the electroless palladium plating solution, i.e., there was dummy plating. When the palladium plating solution was used for the first time, there was no palladium initiation for 900 s. When the palladium plating solution was used for the second time, the palladium initiation appeared at 500 s. When the palladium plating solution was used for the third time, the palladium initiation was even advanced to 200 s. In the process of palladium plating, the higher the temperature, the more active the plating solution was, and the less likely it was to show dummy plating, but the stability also decreased. After the onset potentials separately in the experiments of polarization curves measured by linear scanning voltammetry were obtained, the onset oxidation potential of sodium hypophosphite (EO) shifted negatively with increasing temperature and the onset reduction potential of palladium ion(ER) shifted positively with increasing temperature, and the difference between the EO and ER (|ΔE|) decreased with increasing temperature.TheΔE was the electrochemical information of the electroless palladium plating solution, and also revealed the stability of the plating solution and measured the ease of electroless palladium plating, i.e., the ΔE was associated with the dummy plating. The ΔE<0 indicated that the plating solution was stable and electroless palladium plating needed to be initiated on the surface of the catalyst, while ΔE>0 indicated that the plating solution was unstable and would spontaneously decompose, preventing selective deposition on the surface of the part to be plated. The electroless palladium plating could be initiated normally when |ΔE|≤0.73 V, while the initiation process showed dummy plating when |ΔE|>0.73 V. The concentration of glycine could affect ΔE. When the concentration of glycine was close to 10 g/L, the dummy plating was not obvious, but when there was no glycine or its concentration was greater than 20 g/L, the deposition of palladium was not favored and the dummy plating was likely to occur. The value of ΔE is related to the stability of the electroless palladium plating solution and the occurrence of dummy plating.