The invention relates to a fiber material, and in particular relates to a composite arenga engleri and jute mattress. The composite mattress is prepared through the following steps: preparing arenga engleri fiber: boiling and separating; before loosening, conducting primary bamboo vinegar treatment and secondary bamboo vinegar treatment to jute fiber and arenga engleri fiber; then implementing antibacterial treatment, mixing, dipping and loosening: degumming, carding and shorting, and dipping the short jute fiber and the short arenga engleri fiber which are mixed at a weight ratio of (30-40): (25-50) in lignocellulose aerogel liquid for 15-20min, taking out the mixture, draining off, and loosening and mixing in a loosening machine; carding and forming a net through an airflow: enabling loosened short jute fiber and short arenga engleri fiber drop uniformly from a roller groove through airflow, and uniformly arranging to form a net-shaped half-finished product with an S-shaped cross section; carrying out non-woven punching; roasting at high temperature, wherein the lignocellulose aerogel liquid is prepared by grinding, purifying, freezing and thawing, coagulating and regenerating. The composite arenga engleri and jute mattress disclosed by the invention is sound-insulating and heat-insulating, comfortable and environment-friendly, antibacterial and breathable, and long in service life.