The invention belongs to the technical field of a cable, and relates to a photoelectric composite cable laid in a seabed. The cable comprises multiple fibers, a loose sleeve, a thermal insulation layer, a conductor layer, an insulation layer, a shielding layer, a first protective layer, an inner sheath, a first armored layer, a second protective layer, a second armored layer, a third protective layer and an outer jacket. The first armored layer is formed by spirally twisting first reinforcement elements around the inner sheath in a unidirectional mode by a first pitch; the second armored layer is formed by spirally twisting second reinforcement elements around the second protective layer in a unidirectional mode by a second pitch; the winding directions of the first pitch and the second pitch are opposite; the second pitch is 3 to 5 times the first pitch; the ratio of the first pitch to the external diameter of the inner sheath equals to (3-6):1; the materials of the first reinforcement elements are steel wires or alloy wires; and the materials of the second reinforcement elements are the steel wires or the alloy wires. The cable provided by the invention has the following advantages: the cable can transmit both optical signals and electric power, can also resist bending and torsion, and is more compact in structure, longer in life, smaller in external diameter, lower in cost and lower in transport cost.