A dynamic spectrum allocation method, comprising steps of: allocating, by a centralized node, a spectrum, and transmitting a spectrum allocation result to each communication node, so that the communication node operates on a spectrum resource corresponding to the communication node in accordance with the spectrum allocation result and performs statistics of communication quality measurement information; receiving, by the centralized node, the communication quality measurement information reported by each communication node; and determining, by the centralized node, whether or not it is required to trigger the spectrum re-allocation for each communication node in accordance with the communication quality measurement information about the communication node, and when it is required to trigger the spectrum re-allocation for the communication node, re-allocating the spectrum for the communication node, wherein the method is characterized in that the step of, determining, by the centralized node, whether or not it is required to trigger the spectrum re-allocation for each communication node in accordance with the communication quality measurement information about the communication node comprises: when there are M pieces of communication quality measurement information about the communication node, determining, by the centralized node, decision results Q 1, Q 2,..., Q M representing the communication quality with respect to each piece of communication quality measurement information, and when 1 M * ∑ m = 1 M W m * Q m is greater than a first predetermined threshold, determining that it is required to trigger the spectrum re-allocation for the communication node, wherein Wm represents a weighted value for Qm, and wherein the communication quality measurement information comprises average throughput per resource unit within a time period, a block error rate, BLER, for all users within the time period, and an average interference measurement value within the time period, wherein when the average throughput per resource unit within the time period is less than a second predetermined threshold, a first decision result of said decision results Q 1, Q 2,..., Q M is set equal to a first mark for representing bad communication quality, when the BLER for all the users within the time period is greater than a third predetermined threshold, a second decision result of said decision results Q 1, Q 2,..., Q M is set equal to the first mark for representing bad communication quality, and when the average interference measurement value within the time period is greater than a fourth predetermined threshold, a third decision result of said decision results Q 1, Q 2,..., Q M is set equal to the first mark for representing bad communication quality. allocating, by a centralized node, a spectrum, and transmitting a spectrum allocation result to each communication node, so that the communication node operates on a spectrum resource corresponding to the communication node in accordance with the spectrum allocation result and performs statistics of communication quality measurement information; receiving, by the centralized node, the communication quality measurement information reported by each communication node; and determining, by the centralized node, whether or not it is required to trigger the spectrum re-allocation for each communication node in accordance with the communication quality measurement information about the communication node, and when it is required to trigger the spectrum re-allocation for the communication node, re-allocating the spectrum for the communication node, wherein the method is characterized in that the step of, determining, by the centralized node, whether or not it is required to trigger the spectrum re-allocation for each communication node in accordance with the communication quality measurement information about the communication node comprises: when there are M pieces of communication quality measurement information about the communication node, determining, by the centralized node, decision results Q 1, Q 2,..., Q M representing the communication quality with respect to each piece of communication quality measurement information, and when 1 M * ∑ m = 1 M W m * Q m is greater than a first predetermined threshold, determining that it is required to trigger the spectrum re-allocation for the communication node, wherein Wm represents a weighted value for Qm, and wherein the communication quality measurement information comprises average throughput per resource unit within a time period, a block error rate, BLER, for all users within the time period, and an average interference measurement value within the time period, wherein when the average throughput per resource unit within the time period is less than a second predetermined threshold, a first decision result of said decision results Q 1, Q 2,..., Q M is set equal to a first mark for representing bad communication quality, when the BLER for all the users within the time period is greater than a third predetermined threshold, a second decision result of said decision results Q 1, Q 2,..., Q M is set equal to the first mark for representing bad communication quality, and when the average interference measurement value within the time period is greater than a fourth predetermined threshold, a third decision result of said decision results Q 1, Q 2,..., Q M is set equal to the first mark for representing bad communication quality.