Hulusi is generally divided into treble, alto and bass. The pitch of the gourd is determined by the inner diameter of the bamboo pipe and the position of the opening. The gourd is only the resonance chamber (box) of the musical instrument, and it has no effect on the pitch of the musical instrument. Substantial influence, under normal circumstances, the gourd used for treble cucurbit is smaller, followed by mid-range cucurbit, and larger cucurbit is used for bass cucurbit. Therefore, the size of the gourd is mainly for coordination and beauty with the thickness of the bamboo tube. In principle, the thicker bamboo tube is matched with a larger gourd.

Generally, the size of the gourd is about one-third of the total length of the instrument. Like bamboo flute, suona and other national wind instruments, cucurbit flute has different tunes for each instrument, and several instruments form a set. Like the bamboo flute, the cucurbit flute is tuned by the absolute pitch of the third hole.

Generally divided into three types: high, medium and low, treble cucurbits are usually small C, small D, small F, small G, etc., mid-range cucurbits are usually bB, A, G, F, etc., bass Hulusi is often in major D, major C, major bB, etc. Generally, the commonly used keys are minor D, minor C, bB, G, and F, and A key can also be added to form a set of musical instruments to prepare music of different styles and tones to suit different needs. Commonly used cucurbits include C, G, B, F, etc. Beginners can choose the instrument according to their hand shape and finger length. Generally, children with small hands can choose small C (smaller hole spacing). Or adults can choose bB key (moderate hole spacing), if necessary, can also choose G key, F key (larger hole spacing).