In the development history of liuqin for more than 200 years, various forms of liuqin have appeared, such as the original two-string liuqin, three-string liuqin, four-string liuqin, five-string alto liuqin, seven-string liuqin, and double-resonance box liuqin. The music art of Liuqin has been expanded, and the development space of Liuqin has been expanded.

Ruan Shichun, the chief liuqin performer of the Hong Kong Chinese Orchestra, produced a series of double-sounding box liuqin (soprano, middle and tenor), for which he won the Science and Technology Progress Award of the Ministry of Culture in 1992.

The double-sounding box liuqin is made of the same materials as the general four-string high-pitched liuqin. The back panel is made of hardwood, mainly mahogany, rosewood and rosewood, and the top panel is made of softwood, generally sycamore wood. From the appearance, the double-sounding box liuqin is thicker than ordinary liuqin, and there is a sound window on the back panel. This allows the player to hear the sound he is playing more clearly. The principle is: the front panel of the piano mainly provides vibration, and the back panel mainly provides reflection. The basic sound of the liuqin is that the string vibration is transmitted to the panel by the bridge, and the sound wave is transmitted inward through the panel vibration of the air in the resonance box. When the sound wave hits the back plate, it is reflected in the resonant box, causing the sound wave to generate a standing wave phenomenon, thereby amplifying the volume, and then passing out from the sound window.

The biggest difference between the internal structure of the double resonance box liuqin and the traditional liuqin is that there is an extra layer of cork partitions in the resonance box. Its function is to use the effect of vibration transmission of the sound column, so that the second-layer panel can also generate sound waves, but it also provides reflection at the same time, producing an effect similar to the sound of a violin. The function of the double-resonance box liuqin is not only to increase the volume of the liuqin, but also to provide space for different pitches to generate standing waves, so that the sound of each sound area can be averaged, making the sound more beautiful. This kind of double-resonance box liuqin is not widely used due to its low output and high price. At present, the Taipei City Orchestra and the Experimental Orchestra have adopted the double-resonance box liuqin. The Taipei Liuqin Chamber Orchestra may have the highest concentration of double-resonance box liuqin in the world. group.