Disclosed are a solar junction box and a wire connecting structure of the solar junction box. The solar junction box includes plural first conductive tongues separately and perpendicularly plugged onto a printed circuit board, plural solar panel conducting plates combined to the first conductive tongues, and each solar panel conducting plate including an extension plate connected to a solar panel and a U-shaped snap-in plate bent and extended from the extension plate, and each U-shaped snap-in plate being snapped onto each first conductive tongue, plural insulators sheathed on the solar panel conducting plates, a pair of second conductive tongues separately and flatly attached onto a side of the printed circuit board, and two conducting terminals electrically connected to the pair of second conductive tongues. With the installation of the wire connecting structure, the volume of the solar junction box can be reduced to provide a stable electrical connection.